A deep northwest flow of cold air will be over the region
through Wednesday afternoon. This will result in snow showers
across the mountains tonight and early Wed.
Low pressure will track across southwestern Pennsylvania
Wednesday night. This low will bring a period of light snow to
the area late Wednesday into early Thursday.
A complex weather pattern will be across the region this
weekend, and early next week. This will result in some snow
showers from time to time, but a moderating trend into next
week.

-- End Changed Discussion --

&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...

-- Changed Discussion --

IR loop at 2230Z showing breaking clouds across eastern Ohio and
northwest Pa, as low PWAT arctic air overspreads the region on
northwest flow. Surface dewpoints range from the 20s over
eastern Pa to the single digits in the west. Although the dry
air will hinder lake effect snow overall, long fetch Lake Huron
band is progged by models to slip southward across northern Pa
late tonight. Have timed highest POPs to correlate with arrival
of this band based on latest NAM/Canadian 925mb thte fields.
Based on model blended qpf and an expectation of snow/water
ratios near 20/1 (max omega occurring within DGZ), believe
additional snowfall between 00Z-12Z will range from up to 6
inches over the snowbelt of northwest Warren County, to a fresh
coating across the northeast quadrant of the forecast area.
Despite favorable upslope flow, believe overnight accums across
the Laurel Highlands will be only an inch or less due to the
aforementioned dry air.
For most of the forecast area, the cold air and low wind chills
will be the main story overnight. Temperatures falling into the
teens, combined with gusty winds, will result in wind chills
in the lower single digits late tonight across the southeast
counties and the lower single digits below zero across the
Allegheny Plateau. Passage of upper trough axis and pressure
fall/rise couplet late tonight will likely be accompanied by an
increase in wind gusts during the early morning hours. Latest
Bufkit soundings support frequent gusts between 25-35kts early
Wed morning. Heavy winter coats, hats, and good gloves/mittens
will be in order if going out tonight, especially at the bus
stops Wednesday AM.

-- End Changed Discussion --

&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Key point is it will be a very cold day with lots of wind.
Windchill values will be below 0F in the northwest and range the
single digits above zero over the southeast. Bundle the kids up
for school.
A very cold December kind of day. Snow guns should be blazing at
ski resorts.
The snow should continue though at lesser rates in the northwest
and in the higher terrain of the southwest mountains.
Clouds will increase during the day as a fairly vigorous Alberta
Clipper zips on towards us. Most models weaken it as it passes
over us. But as the rule of clippers go this one should pass
just to our south, the old school sweet spot.
Most of the larger scale models imply 0.1 to 0.25 inches of
QPF. Highest in southwest mountains, possible. Most of the
potential snow will fall after this period. But the GEFS and
SREF imply some snow could arrive in the southwest in the late
afternoon or early evening. Most of the snow will fall after 7
PM.
I did up QPF and POPS some Wednesday night.
Amounts still below advisory. System is moving awful fast for
much snow.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Complex pattern for late in the week into next week.
I did lower temperatures and dewpoints for the first part of the
weekend, as the northern system looks stronger now, may result
in cold air building southward into the area.
Also cut winds and gusts down, as I have done the last few days,
given the trend away from a deep low on Sunday.
Models show southern branch of the westerlies trying to come
into play on the large scale next week, but for now did not go
real high with POPS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
The cold front is still working its way across our easternmost
counties. Behind the initial surge of cold air winds have come
around to the west/northwest with gusty winds in the higher
elevations. Gusty winds will slowly spread east.
Low cigs are behind the front. But most of the MVFR/IFR is in
the higher terrain. Snow and blowing snow will affect the
southwestern mountains and northwestern areas for the next 12 to
24 hours. Blowing snow too. KBFD and KJST will be the two spots
to check the weather carefully before take off.
Most other areas main concern will be increasing and gusty
winds. Some snow showers will affect KAOO and KUNV at times but
nothing significant nor long lasting but periods of MVFR will
happen.
Farther east mainly gusty winds.
A short wave could bring light snow into western areas Wednesday
afternoon into Thursday. This could lower CIG/VIS in many
western areas from KJST-KAOO-KUNV but this is beyond our current
forecast period.
Outlook...
Wed...Snow showers with IFR NW Mtns. Sct snow showers with MVFR
NW half. Otherwise VFR.
Wed night...Alberta Clipper could bring light snow and more
widespread reductions.
Thu-Fri...Sct snow showers NW. Reductions west and southwest mts.
Sat...Mainly VFR. Perhaps a snow shower north and east early.
Sun...Mainly VFR. Perhaps a few showers late.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 1 PM EST Wednesday for PAZ005-
010-017-024-033.
Lake Effect SnowWarning until 1 PM EST Wednesday for PAZ004.
&&
$$
SYNOPSIS...Lambert/Martin
NEAR TERM...Fitzgerald
SHORT TERM...Grumm/Martin
LONG TERM...Martin
AVIATION...Grumm/Martin